The application provides an assembly comprising a housing (20) having an electrical housing connector (50) and a strip port (40) for a BGM sensor arranged in the vicinity of the electrical connector. The assembly further comprises an external electrical connector (60) adapted for releasable connection to the housing connector, wherein the external electrical connector comprises a portion (62) adapted to block the port opening when the external electrical connector is connected to the housing connector, thereby preventing insertion of a strip in the port when the two connectors are connected to each other. In this way it is prevented in a simple and cost-effective manner that a patient via an inserted strip is subjected to a too high voltage or current supplied to the circuitry of the electronic device.